During operation of an internal combustion engine, it is desirable to control the formation and emission of certain gases, such as the oxides of nitrogen (NO.sub.x). One method of achieving this result is the use of exhaust gas recirculation (EGR) which is a process whereby exhaust gases are selectively routed from the exhaust manifold to the intake manifold of the internal combustion engine. The use of EGR reduces the amount of NO.sub.x produced during operation of the internal combustion engine. In particular, NO.sub.x is produced when nitrogen and oxygen are combined at high temperatures associated with combustion. The presence of chemically inert gases, such as those gases found in the exhaust of the engine, inhibits nitrogen atoms from bonding with oxygen atoms thereby reducing NO.sub.x production.
While the use of inert exhaust gases in the above manner reduces NO.sub.x production, engine performance may be disadvantageously affected by the introduction of the exhaust gases into the intake manifold of the engine. In particular, the exhaust gases are generally extremely hot when introduced into the engine. The additional heat associated with the exhaust gases may decrease the efficiency of the engine. In order to reduce the effects of the hot gases, a heat exchanger, or cooler, is installed to cool the hot exhaust gases prior to introducing the exhaust gases into the intake manifold of the engine. This allows NO.sub.x reduction, yet lessens the disadvantageous effects of the additional heat associated with the exhaust gases.
One type of internal combustion engine, which is commonly used in heavy machinery, is known as a "cross flow engine". In a cross flow engine, the intake manifold is mounted on the opposite side of the engine from the exhaust manifold. If an EGR system is installed on a cross flow engine, exhaust gases must be routed over, under, or around the periphery of the engine in order to be advanced from the exhaust manifold to the intake manifold. One drawback associated with mounting an EGR system on a cross flow engine is that there is often inadequate space in the engine compartment for mounting the cooler and associated lines onto the engine. Furthermore, it is often difficult to route the associated lines from one side of the engine to the other due to the number and configuration of the engine components that are positioned between the exhaust manifold and the intake manifold.
What is needed, therefore, is an apparatus and method for cooling exhaust gases which overcome one or more of the above-mentioned drawbacks.